Divisibility Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u Submit Status Practice HDU 3335 Appoint description:  System Crawler  (2015-04-10) Description As we know,the fzu AekdyCoin is famous of math,especially in the…

分析: dlx重复覆盖的巧用,重复覆盖的原理恰好符合本题的筛选方式,即选择一个数后,该数的倍数或约数可以保证在之后的搜索中不会被选择 于是修改一下启发函数,求解最大的重复覆盖即可.   其实不一定不被选择,只是选择以后,要么达不成目标,要不达到目标,也不如不选择更优   举下面的例子 3 2 3 6 答案一看就是 2 初始的dancing links的表示是这样的       2   3   6 2    1   0   1 3    0   1   1 6    1   1   1 然后肯定先…

Description As we know,the fzu AekdyCoin is famous of math,especially in the field of number theory.So,many people call him "the descendant of Chen Jingrun",which brings him a good reputation.  AekdyCoin also plays an important role in the ACM_D…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5046 题意:n个城市修建m个机场,使得每个城市到最近进场的最大值最小. 思路:二分+dlx搜索判定. #include <iostream> #include <map> #include <string> #include <stdio.h> #include <vector> #include <set> #include <a…

http://acm.hdu.edu.cn/showproblem.php?pid=3335 题意:在给出的n个数中找出一个集合,使得其中的数互不整除,求该集合最大的元素数量 首先要对输入的数去重,输入的数是64位的,开始没用__int64坑了好久 一上来我以为是求二分图最大独立集,利用相反的关系建边(整除即连边),再用n去减,这样发现没过样例(因为拆点了,求得的最大匹配数要除以二),想了下发现这个解法的bug,用最大独立集求出来的互不整除的最多元素每两个之间关系是双向的,相互不整除,a不整除b…

http://acm.hdu.edu.cn/showproblem.php?pid=5046 n城市建k机场使得,是每个城市最近机场的距离的最大值最小化 二分+DLX 模板题 #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <string> #include <queue> #include <vector>…

2分答案+DLX判断可行 不使用的估计函数的可重复覆盖的搜索树将十分庞大 #include <iostream> #include <cstring> #include <cstdio> #include <cmath> #include <vector> using namespace std; #define FOR(i,A,s) for(int i = A[s]; i != s; i = A[i]) #define exp 1e-8 , M…

Air Raid Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 3122    Accepted Submission(s): 2027 Problem Description Consider a town where all the streets are one-way and each street leads from on…

Fire station Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1308    Accepted Submission(s): 434 Problem Description A city's map can be seen as a two dimensional plane. There are N houses in…

Radar Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2882    Accepted Submission(s): 1113 Problem Description N cities of the Java Kingdom need to be covered by radars for being in a state of w…